text: /* e_asinf.c -- float version of e_asin.c.
   * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   */
  
  /*
   * ====================================================
   * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   *
   * Developed at SunPro, a Sun Microsystems, Inc. business.
   * Permission to use, copy, modify, and distribute this
   * software is freely granted, provided that this notice 
   * is preserved.
   * ====================================================
   */
  
  #if defined(LIBM_SCCS) && !defined(lint)
  static char rcsid[] = "$NetBSD: e_asinf.c,v 1.5 1995/05/12 04:57:25 jtc Exp $";
  #endif
  
  #include "math.h"
  #include "math_private.h"
  
  static const float 
  one =  1.0000000000e+00, /* 0x3F800000 */
  huge =  1.000e+30,
  pio2_hi =  1.5707962513e+00, /* 0x3fc90fda */
  pio2_lo =  7.5497894159e-08, /* 0x33a22168 */
  pio4_hi =  7.8539818525e-01, /* 0x3f490fdb */
  	/* coefficient for R(x^2) */
  pS0 =  1.6666667163e-01, /* 0x3e2aaaab */
  pS1 = -3.2556581497e-01, /* 0xbea6b090 */
  pS2 =  2.0121252537e-01, /* 0x3e4e0aa8 */
  pS3 = -4.0055535734e-02, /* 0xbd241146 */
  pS4 =  7.9153501429e-04, /* 0x3a4f7f04 */
  pS5 =  3.4793309169e-05, /* 0x3811ef08 */
  qS1 = -2.4033949375e+00, /* 0xc019d139 */
  qS2 =  2.0209457874e+00, /* 0x4001572d */
  qS3 = -6.8828397989e-01, /* 0xbf303361 */
  qS4 =  7.7038154006e-02; /* 0x3d9dc62e */
  
  #ifdef __MINGW32CE__
  #define __ieee754_sqrtf sqrtf
  #endif
  
  float
  __ieee754_asinf(float x)
  {
  	float t,w,p,q,c,r,s;
  	int32_t hx,ix;
  	GET_FLOAT_WORD(hx,x);
  	ix = hx&0x7fffffff;
  	if(ix==0x3f800000) {
  		/* asin(1)=+-pi/2 with inexact */
  	    return x*pio2_hi+x*pio2_lo;	
  	} else if(ix> 0x3f800000) {	/* |x|>= 1 */
  	    return (x-x)/(x-x);		/* asin(|x|>1) is NaN */   
  	} else if (ix<0x3f000000) {	/* |x|<0.5 */
  	    if(ix<0x32000000) {		/* if |x| < 2**-27 */
  		if(huge+x>one) return x;/* return x with inexact if x!=0*/
  	    } else 
  		t = x*x;
  		p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5)))));
  		q = one+t*(qS1+t*(qS2+t*(qS3+t*qS4)));
  		w = p/q;
  		return x+x*w;
  	}
  	/* 1> |x|>= 0.5 */
  	w = one-fabsf(x);
  	t = w*(float)0.5;
  	p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5)))));
  	q = one+t*(qS1+t*(qS2+t*(qS3+t*qS4)));
  	s = __ieee754_sqrtf(t);
  	if(ix>=0x3F79999A) { 	/* if |x| > 0.975 */
  	    w = p/q;
  	    t = pio2_hi-((float)2.0*(s+s*w)-pio2_lo);
  	} else {
  	    int32_t iw;
  	    w  = s;
  	    GET_FLOAT_WORD(iw,w);
  	    SET_FLOAT_WORD(w,iw&0xfffff000);
  	    c  = (t-w*w)/(s+w);
  	    r  = p/q;
  	    p  = (float)2.0*s*r-(pio2_lo-(float)2.0*c);
  	    q  = pio4_hi-(float)2.0*w;
  	    t  = pio4_hi-(p-q);
  	}    
  	if(hx>0) return t; else return -t;    
  }
  